Bicyclic peptide-based assay for uPA cancer biomarker

The use of synthetic bioreceptors to develop biosensing platforms has been recently gaining momentum. This case study compares the performance of a biosensing platform for the human biomarker urokinase-type plasminogen activator (h-uPA) when using two bicyclic peptides (P(1 )and P-2) with different affinities for the target protein. The bioreceptors P-1 and P(2 )were immobilized on magnetic microbeads and tested within a sandwich type affinity electrochemical assay. Apart from enabling h-uPA quantification at nanomolar levels (105.8 ng/mL for P1 and 32.5 ng/mL for P-2), this case study showed the potential of synthetic bicyclic peptides applicability and how bioreceptor affinity can influence the performance of the final sensing platform.